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History of glass
Glass has existed naturally since many thousands of years. Humankind used glass for the first time 100,000 years ago in its obsidian form (volcanic formed glass) to make tools, cutting weapon and jewels.
(Source : www.infovitrail.com)
Origins:
The first glass made by man come from Mesopotamia, Syria or Egypt 3000 years BC. They were not transparent, but opaque, green or blue. According to Pliny the Elder (23-79 AD) the Phoenicians merchants, while cooking their meals on the shores of Belus River in cauldrons supported by blocks of natron, would have seen an unknown and strange substance melting. That’s only part of the legend, because the creation of glass needs a temperature of 1300°C.
The first flowering: 15th Century BC
The creation of ovens allow higher temperatures, material is shaped more easily. Glass becomes transparent and a growing business is developed around precious stone imitations.
The first hollowed glass works (vase, pots, bottles) appeared in the same time; they are melted. Enamel appears around 1500 BC It’s a glass-like substance made of a transparent color, fondant, dyed in the substance adding certain metallic oxide.
Blown glass advent: 1st Century BC
At this time, Syrians would have invented the blow cane. From there, the knowledge for the process passed to Italy, then Gaul and Spain. At the same time, Sidonians (Phoenicia) invented the transparent glass, probably because of the purity of the sand in the area and the presence of natron. That discovery gave birth to a strong hollow glass industry. With the development of cane-blowing, the craftsmen were further from the heat source and were able to shape parts of many centimeters.
The transparent glass has appeared then and spread starting from the 3rd century onwards, obtained by adding manganese, which acts as a purifier. The natural shade of glass, blue-green, comes from metallic oxides contained in the sand that is used in the process.
First traces of melted flat glass (5 to 6 mm).
That glass of relative transparency was used to make windows (Pompei). Before that, people used thin plates of mica or alabaster.
The blown flat glass: 5th and 10th Century
Two techniques that appeared simultaneously:
- Crown-blowing: produced in the West of France and in England where the production lasted until the 19th century. The flat glass has boomed only from the creation of this new process. It was done from a flat bottom blown vase that turned facing the opening of an oven.
- Muff-blowing: produced in the Eastern and Central Europe, it’s a cylinder of glass obtained by elongating the parison gathered by the glass craftsman and then cracked, softened and flattened. These processes were used during the Middle Ages to make stained glass.
Windowpane glass
The use of windowpane glass was known from the Romans, but not widely spread in civilian architecture until the 15th century. The ways to prevent the wind and rain to enter the houses was, then, basic means : wooden shutter, waxed cloth, skins or oiled paper that were not well protected from wire mesh. During the Middle Ages, there was a long stagnation of the windowpane glass in houses where the windows length diminished were almost never glassed.
At the turn of the 16th century, the first glassmaking shop for windowpanes was born in Bézu-la-Forêt in the Eure and the flat sheets (‘plats de verre’) were invented by Philippe Cacqueray. In 1698, in the castle of Saint-Gobain, Lucas de Nehou fine-tuned the process for making glass products by using the flow of fused material in a mold. Nowadays, the windowpane glass is obtained by floating, which is manufacturing process for flat glass in an bowl-oven with a flow of material on a pool of melting tin. This is called floating glass. The stained glass are normally made with the old process.